Gordon Brown could become the first British prime minister to agreed to a US presidential-style television debate at the next general election, it emerged today.

Peter Mandelson, the business secretary and deputy prime minister in all but name, fuelled speculation that Brown would be prepared to agree to a television clash with the Tory leader, David Cameron, when asked about the prospect in a newspaper interview.

Tony Blair repeatedly refused calls from opposition leaders for a live debate, insisting that weekly question sessions in the Commons were enough.

Asked by the Evening Standard whether Brown would agree to such a clash, Mandelson said: "I don't think Gordon would have a problem with that.

"While Cameron is good with words, he doesn't have the ideas or policies to back them. I think people would see through the smile.

"The more the public sees of them, the more they'd realise that Gordon is the man with the substance."

Mandelson argued that a debate could expose Cameron's weaknesses, saying the Conservative leader "lacks substance" and "might come across as someone who exudes effortless superiority in public but loses his rag in private".

High-profile TV showdowns are a fixture in the US, where they are seen as having the potential to turn elections.

But while opposition politicians on this side of the Atlantic have often laid down the gauntlet, successive prime ministers have refused to take it up.

The strategy could be particularly high risk for Brown, who is often seen as coming off worse in Commons exchanges with Cameron.

The Tory leader said he would be "delighted" to have the chance to go head to head with the prime minister.

"This is great news. I have always supported television debates at election time between the leaders of the parties," he told Sky News.

"I have pressed Gordon about it in the House of Commons before and he was totally against it. If he has changed his mind, I will be delighted.

"I think television debates will help engage the public, help actually answer some of the questions at the heart of the election, would help bring the election alive in some way.

"We had television debates for the leadership of the Conservative party. I took part in those and ... would be delighted to take part in TV debates for the general election."